Slow spinodal decomposition in binary liquid mixtures of polymers

Abstract

Isothermal demixing process of binary polymer mixtures of SBR (styrene–butadiene random copolymer) and polybutadiene at deep quench depths was investigated by time‐resolved light scattering technique. The results indicated that the systems undergo extremely slow spinodal decomposition of the type as adequately characterized by Cahn’s linearized theory in the e a r l y s t a g e and in the s m a l l q r e g i m e (q≲q max≂105 cm− 1) covered in this experiment where q is wave number of growing fluctuations and q max is the q value having maximum growth rate. The spinodal decomposition studied in this work was that in the diffusion‐control regime, and in the slowest case of the decomposition, the early stage was found to extend up to about 80 min, corresponding to the reduced time τ about 2.7. The shortest reduced time achieved in this experiment is about 0.03.